Means for cementing wells



T. R. NICHOLS MEANS FOR CEMENTING WELLS March 25 1924.

Filed ma 24 1921 3 Sheets-Sheet 1 THA ch 0225 INVENTOR ATTORNEY arch 25 T. R. NICHOLS MEANS FOR CEMENTING WELLS Filed May 24, 1921 I5 Sheets-Sheet 2 ERJWehob INVENTOR ATTORN EY March 25, 1924. 11,487,797

7 T. R. NICHOLS MEANS FOR CEMENTING WELLS Filed May 24, 1921 5 Sheets-Sheet 5 TRJWchols INVENTOR ATTO RN EY Patented Mar. 25, 1924.

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TROY RAYMOND NICHOLS, OF TONKAWA, MISSOURI.

MEANS FOR CEMENTING WELLS.

Application filed may 24, 1921. Serial No. 172,302.

provements in Means for Cementing Wells,

of which the following is a specification.

This invention relates to a means for cementing oil wells and the like and to a device for preventing the cement from being forced back through the casing before it can harden.

The object of the invention is to fill the space between the wall of the well and the casing with cement so as to prevent water and other substances from leaking in through it and around the bottom of the casing and to prevent gas pressure from injuring the well.

Another object of the invention is to prevent the cement fro-m being forced back through the casing by any pressure in the well without keeping the casing filled with the fluid pressur This invention also consists in certain other features of construction. and, in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawings and specifically pointed out in the claim. In describing my invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which Figure 1 is a diagrammatic sectional view showing how a fluid is forced through the casing and up through the well outside of the casing to prove that the well is in condition' for cement.

Figure 2 is a plan view, partly in section, of Figure 1.

Figures 3 and 4: are diagrammatic sectional views showing the manner of carrying out my invention. 0

v igure 5 is an enlarged view of my 1mproved plug.

Figure 6 is a section on lme 6-6 of Figure 5. K

Figure 7 is a plan view of the plug shown in Figure 5.

Figure 8 is an elevati dn of the bottom p figure 9 is asecti niondine 9 1-9 of Figure 8.

Figure 10 is a longitudinal sectional view through the lower part of the plug shown in Figure 8.

In the drawings A indicates the well and B the casing within the well. -After the well is drilled to about the top of the oil sand the casing is put into the well, the (casing extending to within about three feet of the bottom of the well and said casing is of such a diameter as to leave a space between itself and the wall of the well. The casing is held at its top by elevators or slips. A bushing 1 is screwed to the top of the casing to close thesame and this bushing is connected by piping 2 with a pump or the like so that fluid, such as thin mud or water, can be forced into the casing. This fluid will pass through the casing to the bottom of the well and will then pass u between the walls of the well and the casing and flow from the top of the well. If the fluid flows from the top of the well it will show that the circulation is correct and that the cementing process can be carried out.

I provide a pair of plugs 3 and 4. The plug 3 is formed of the strip 5 having the right angularly extending strips Gsecured to its center and the discs 7 at the ends, some of these discs being preferably formed of Wood and others of leather or the like and said discs being so formed as to make a snug fit within the-cylinder. Upwardly extending toothed dogs 8 are secured to the strip 5 adjacent the edges and springs 9 tend to hold these dogs with their toothed ends in engagement with the casing, the parts being so arranged that the plug can easily pass down the casing but cannot be forced upwardly through the casing. Where the plug is to be used with thedrill pipe I place extra discs 7 at the top of the plug, these discs being of smaller diameter than the other discs and being adapted to be engaged by the drill rod. Plug 4 is made somewhat similar to plug 3 though need be used on this plug.

This plug 4 is laced in the casing after removing the bus ing 1 and then cement is forced in the casing through the piping 2 and bushing 1, this cement pushing the plug only a few discs 1 ahead of it towards the bottom ofthe casagain to force the plugs and the cement downwardly. Instead of using a fluid pressure the drill rodcan be placed upon the top of the plug 3 to force the same downwardly. When forcing the cement down through the casing it is necessary to follow with a measuring line in order to tell when the cement is at thejproper place. l-Vhen the drill pipe is used the measuring lineis run down inside the same and a screw plug 2' is placed in piping 2 for this purpose.

The lower plug 4 will finally pass from the bottom of the casing so as to permit the cement to pass out of the casing and the continued pressure upon the plug 3 will force the cement upwardly through the space between the well and the casing. When plug 3 has reached a point near the bottom of the casing the cement will be in its proper place and then the casing can be let down to the bottom of the well. This will usually prevent the cement from being forced back into the casing but if the casing'should not properly seat itself so that' pressure or gravity will act to force the cement back into the casing this will be prevented by the dogs on the plug 3 engaging the walls of the casing and preventing upward movement of the same. After the cement has set the plugs are removed by a boring tool as this can be easily done as the plugs are made of woodor similar material.

My plug is also useful in case the fluid pressure should become inactive for any reason as the plug will hold the cement against upward pressure and the drill pipe could be used to push the plugs and cement the remaining distance. This will prevent the cement from hardening while the fluid pressure pump is being repaired.

Attention is called to the fact that the operation can be completed by the drill pipe,

or other means, if the pump should fail for any reason. If the drill rig is a standard rig instead of a rotary one the drill bit and stem can be used for forcing the plugs and cement through the casing. -With my invention it is not necessary to fill the casing full of fluid to seal the same.

It is thought from the foregoing description that the advantages and novel features of my invention will be readily apparent.

the top piston to force the piston and'mixture to the bottom of the well and spring controlled dogs on the top piston for preventing upward movement of the same in the casing.

In testimony whereof I afiix my signature.

- TROY RAYMOND NICHOLS. 

